Our sleep studies are based on a long-term commitment to contribute to the identification of patient clusters by examining the relationship of sleep abnormalities to clinical status, pharmacological response, and other biological criteria. We believe that the diagnostic process will be strengthened by the addition of biological criteria, and that this strengthening will result in earlier detection and treatment intervention in psychiatric illness. Our specific objectives are: to understand the internal dynamics of sleep abnormalities found in psychiatric illness and to relate them to the two process model of sleep regulation; to determine whether certain sleep state abnormalities have any diagnostic specificity or whether they occur across a broad spectrum of psychiatric illness; and to determine how sleep pathologies covary with clinical symptoms as well as with neuroendocrine and neurochemical measures. We will study five subject groups: normal controls, schizophrenics, and patients with schizoaffective disorder, major depressive disorder, and borderline personality disorder. All subjects will undergo three nocturnal polysomnograms, a day-long Multiple Sleep Latency Test, a blood draw for cortisol levels, and a lumbar puncture for determination of CSF neurotransmitter metabolite levels. They will be diagnosed by the staff of the CRC and will be rated weekly for pattern and severity of clinical symptoms. Among the hypotheses we will test are the following: i) low REM latency is not a specific marker for major depressive disorder since low REM latencies will be found in schizophrenia, schizoaffective disorder, and borderline personality disorder; ii) within and across diagnoses, low REM latency will correlate with the amount of delta sleep in the first NREM cycle; iii) REM latency, delta sleep and total sleep time are positively correlated with CSF 5-HIAA in both schizophrenia and major depressive disorder; iv) REM eye movements will correlate directly with blood cortisol levels both within and across diagnoses; and v) the level of the sleep-dependent process S during the day is less in schizophrenia than in depressive disorder, so that schizophrenics will have significantly longer sleep latencies when measured by the MSLT.